Improvement in inks for canceling



UNITED STATES PATENT OFFICE.

CHARLES o. EGERTON, or BALTIMORE, MARYLAND.

I MPROVEMENT IN' INKS FQR CANCELING.

Specification forming part of Letters Patent No. 198,090, dated December11, 1877; application filed To all whom it may concern:

Be it known that I, O. CALVERT EGERTON, of the city of Baltimore, Stateof Maryland, have invented certain new and useful Improvements inCanceling-Inks; and I hereby declare the same to be fully, clearly, andexactly described as follows:

This invention has for its object to furnish an ink for use in cancelingpostage and revenue stamps, which ink shall be practically indelible.

It is obvious that a coloring matter in a state of true solution iswholly inapplicable to this purpose, since excess of the solvent willentirely remove the coloring matter.

A pigment in a state of mechanical suspension, and applied to thesurface of the stamp, is equally removable, since the solution of thesuspending material will leave the coloring matter without attachment tothe paper, and enable it to be washed or brushed away.

A theoretically perfect cancel would consist, then, in the liberation ofa practically insoluble coloring matter-such as carbonin the body of thepaper of the stampsuch, for instance, as the decomposition of ahydrocarbon turpentine) by chlorine in the paper itself. uch a process,for obvious reasons, is out of the question; but by the use of my inkequivalent results are secured byentirely different.

means.

I compose the ink of two or more coloring matters, one of which shall bepractically insoluble, and mechanically bury it in the paper by havingan abrading material as an ingredient of the ink. i

To this end I compose my ink of the following ingredients iodine,indigo, red and blue aniline, iron-rust, brickdust, muriatic acid, andalcohol. These are taken, except the last October 29, 1877.

named, in about equal proportions, and mixed with the alcohol, beingthoroughly incorporated by grinding, and brought .to the consistency ofprinters ink, when the composition is ready for use. .It is applied bythe usual handstainp, or in any other convenient manner.

Before the cancel-mark so formed can be eradicated the material of thestamp is reduced to pulp; in a word, the reuse of th stamp is renderedimpossible.

WVith my ink the aniline furnishes a soluble coloring matter of greatintensity, while the practically insoluble indigo is carried into thebody of the paper by means of the gritty or abrading materials-viz., theiron-rust and brick-dust. Before the color can be dissolved, which isthereby practically pressed into the stamp-paper, the reagents necessaryto effect such solution will inevitable destroy the stamp itself. i

As a substitute for the indigo, printers ink, or other matter containingcarbon, may be used; and instead of the abrading agents named, powderedflint, or substances of similar nature, may be employed.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. A canceling-ink consisting of two or more coloring materials, one ofwhich is practically insoluble, and an abrading material, substantiallyas described.

2. The ink herein described, consisting of iodine, indigo, iron-rust,brick-dust, red and blue aniline, muriatic acid, and alcohol,substantially as set forth.

0. CALVERT EGERTON.

Witnesses:

R. D. WILLIAMS, G. H. PIsrEL.

